774 ■ NEW YORK STATE MUSEUM 



PLATE 14 



Genus didymograptus McCoy 



See pi. 13, 15 



Didymograptus extensus Hall (sp.) 



Page 668 

 See pi. 13 



1, 2 Rhabdosoraes showing the large size attained by this species 



Graptolite bed 2 of the Deep kill section 

 3, 4 Young rhabdosomes with primary disks. The disks are shaded too 

 dark. x2 



Graptolite bed 1 of the Deep kill section 



Didymograptus nitidus Hall (sp.) 



Page 671 

 See pi. 18 



5-6 Young rhabdosomes with primary disks. The disks are shaded too 

 dark. x2 

 Graptolite bed 1 of the Deep kill section 



Didymograptus patulus Hall (sp.) 



Page 674 

 See pi. 13 



7 Young rhabdosome with fragmentary primary disk. x2 

 Graptolite bed 1 of the Deep kill section 



Didymograptus filiformis Tullberg 



8-11 Various aspects of young rhabdosomes. x2 

 Graptolite bed 2 of the Deep kill section 



12 Mature specimen 



Graptolite bed 1 of the Deep kill section 



13 Rhabdosome 



Ash hill quarry, Mt Moreno, Columbia oo. N. Y. 



14 Young rhabdosome ; obverse side, x6^, to show character of sicula and 



thecae 

 Graptolite bed 2 of the Deep kill section 



